The present invention relates to the field of optical repeaters and, more particularly, to an apparatus and method for assembling amplifier assemblies for use in optical repeaters.
In an undersea optical transmission system, optical signals that are transmitted through an optical fiber cable become attenuated over the length of the cable, which may span thousands of miles. To compensate for this signal attenuation, optical repeaters are strategically positioned along the length of the cable.
In a typical optical repeater, the optical fiber cable carrying the optical signal enters the repeater and is coupled through at least one amplifier and various components, such as optical couplers and decouplers, before exiting the repeater. These optical components are coupled to one another via optical fibers as well. Repeaters are housed in a sealed structure that protects the repeaters from environmental damage.
FIG. 1 illustrates a known submarine optical repeater 2 having a cylindrical member 4 and a pair of end plates 6 closing the opposite ends of the cylindrical member 4. An internal structure 8 including a radiating/shock absorbing member 7, is included within repeater 2. The internal structure 8 has two module assemblies 10 and 12. Submarine optical cables 14 are connected to the opposite ends of optical repeater 2. Each submarine optical cable 14 has a power cable 16 for feeding a series constant current and has an optical fiber cable 18. The power cable 16 and the optical fiber cable 18 of each submarine optical cable 14 are introduced into optical repeater 2 through a bushing 20 inserted through a substantially central portion of each end plate 6, and are connected electrically and optically to the internal structure 8.
FIG. 2 is a perspective view of one of the module assemblies (either module assembly 10 or 12) which is included in internal structure 8 as shown in FIG. 1. Typically, the module assembly includes a common module 70, a drive circuit module 72 provided on an upper side of common module 70 and a power supply module 74 provided on a lower side of the common module 70. The common module 70 has a common frame 80 consisting of an upper common frame 76 and a lower common frame 78 integrated together. The modules 72 and 74 are stacked together horizontally and can be clamped together by bolts or by any other method for connecting the modules. Each of these modules also includes a means for providing electrical and optical connections, which can include either interconnections between the modules or interconnections of the input and output power to and from power cable 16 and interconnections of input and output optical signal connections to and from optical cable 18.
As can be seen in FIG. 2, the optical interconnection 79 between the modules creates a tangled web of optical fibers that could be damaged as a result of, among other reasons, twisting, tangling or bending of the fibers. Moreover, incorporating additional module assemblies would greatly increase the complication of interconnection of the modules and could increase the size of the optical repeater. Finally, repairing any of the components in the repeater would be very difficult because of the complicated interconnection of the components.
Therefore, it would be desirable to provide an improved apparatus and method for arranging module assemblies in an optical repeater that would avoid greatly increasing the overall size of the optical repeater, protect interconnecting optical fibers, and provide accessibility for maintenance purposes.
An optical repeater includes an internal structure having defined therein a longitudinal plane. The internal structure includes and a plurality of base modules. The base modules have a front and a back face and a plurality of sides with the faces positioned substantially perpendicular to the longitudinal plane of the internal structure. The optical repeater further includes a top module disposed substantially perpendicular to one of the plurality of sides the base modules.
A method for assembling an optical repeater includes providing and internal structure and defining a longitudinal plane therein. The method also includes providing a plurality of modules having a front and a back face and a plurality of sides such that the faces of the base modules are positioned substantially perpendicular to the longitudinal plane of the internal structure. The method further includes providing a top module disposed substantially perpendicular to one of the plurality of sides of the base modules.